/[pcre]/code/trunk/doc/html/pcretest.html

Diff of /code/trunk/doc/html/pcretest.html

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-revision 63 by nigel,
Sat Feb 24 21:40:03 2007 UTC
+revision 77 by nigel,
Sat Feb 24 21:40:45 2007 UTC
 Line 3
  <title>pcretest specification</title>
  </head>
  <body bgcolor="#FFFFFF" text="#00005A" link="#0066FF" alink="#3399FF" vlink="#2222BB">
- This HTML document has been generated automatically from the original man page.
+ <h1>pcretest man page</h1>
- If there is any nonsense in it, please consult the man page, in case the
+ <p>
- conversion went wrong.<br>
+ Return to the <a href="index.html">PCRE index page</a>.
+ </p>
+ <p>
+ This page is part of the PCRE HTML documentation. It was generated automatically
+ from the original man page. If there is any nonsense in it, please consult the
+ man page, in case the conversion went wrong.
+ <br>
  <ul>
  <li><a name="TOC1" href="#SEC1">SYNOPSIS</a>
  <li><a name="TOC2" href="#SEC2">OPTIONS</a>
  <li><a name="TOC3" href="#SEC3">DESCRIPTION</a>
  <li><a name="TOC4" href="#SEC4">PATTERN MODIFIERS</a>
- <li><a name="TOC5" href="#SEC5">CALLOUTS</a>
+ <li><a name="TOC5" href="#SEC5">DATA LINES</a>
- <li><a name="TOC6" href="#SEC6">DATA LINES</a>
+ <li><a name="TOC6" href="#SEC6">THE ALTERNATIVE MATCHING FUNCTION</a>
- <li><a name="TOC7" href="#SEC7">OUTPUT FROM PCRETEST</a>
+ <li><a name="TOC7" href="#SEC7">DEFAULT OUTPUT FROM PCRETEST</a>
- <li><a name="TOC8" href="#SEC8">AUTHOR</a>
+ <li><a name="TOC8" href="#SEC8">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a>
+ <li><a name="TOC9" href="#SEC9">RESTARTING AFTER A PARTIAL MATCH</a>
+ <li><a name="TOC10" href="#SEC10">CALLOUTS</a>
+ <li><a name="TOC11" href="#SEC11">SAVING AND RELOADING COMPILED PATTERNS</a>
+ <li><a name="TOC12" href="#SEC12">AUTHOR</a>
  </ul>
  <br><a name="SEC1" href="#TOC1">SYNOPSIS</a><br>
  <P>
- <b>pcretest [-d] [-i] [-m] [-o osize] [-p] [-t] [source] [destination]</b>
+ <b>pcretest [-C] [-d] [-dfa] [-i] [-m] [-o osize] [-p] [-t] [source]</b>
+ <b>[destination]</b>
  </P>
  <P>
  <b>pcretest</b> was written as a test program for the PCRE regular expression
-Line 26 
 library itself, but it can also be used
+Line 37 
 library itself, but it can also be used
  expressions. This document describes the features of the test program; for
  details of the regular expressions themselves, see the
  <a href="pcrepattern.html"><b>pcrepattern</b></a>
- documentation. For details of PCRE and its options, see the
+ documentation. For details of the PCRE library function calls and their
+ options, see the
  <a href="pcreapi.html"><b>pcreapi</b></a>
  documentation.
  </P>
-Line 38 
 about the optional features that are inc
+Line 50 
 about the optional features that are inc
  </P>
  <P>
  <b>-d</b>
- Behave as if each regex had the <b>/D</b> modifier (see below); the internal
+ Behave as if each regex has the <b>/D</b> (debug) modifier; the internal
  form is output after compilation.
  </P>
  <P>
+ <b>-dfa</b>
+ Behave as if each data line contains the \D escape sequence; this causes the
+ alternative matching function, <b>pcre_dfa_exec()</b>, to be used instead of the
+ standard <b>pcre_exec()</b> function (more detail is given below).
+ </P>
+ <P>
  <b>-i</b>
- Behave as if each regex had the <b>/I</b> modifier; information about the
+ Behave as if each regex has the <b>/I</b> modifier; information about the
  compiled pattern is given after compilation.
  </P>
  <P>
  <b>-m</b>
  Output the size of each compiled pattern after it has been compiled. This is
- equivalent to adding /M to each regular expression. For compatibility with
+ equivalent to adding <b>/M</b> to each regular expression. For compatibility
- earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
+ with earlier versions of pcretest, <b>-s</b> is a synonym for <b>-m</b>.
  </P>
  <P>
  <b>-o</b> <i>osize</i>
- Set the number of elements in the output vector that is used when calling PCRE
+ Set the number of elements in the output vector that is used when calling
- to be <i>osize</i>. The default value is 45, which is enough for 14 capturing
+ <b>pcre_exec()</b> to be <i>osize</i>. The default value is 45, which is enough
- subexpressions. The vector size can be changed for individual matching calls by
+ for 14 capturing subexpressions. The vector size can be changed for individual
- including \O in the data line (see below).
+ matching calls by including \O in the data line (see below).
  </P>
  <P>
  <b>-p</b>
- Behave as if each regex has <b>/P</b> modifier; the POSIX wrapper API is used
+ Behave as if each regex has the <b>/P</b> modifier; the POSIX wrapper API is
- to call PCRE. None of the other options has any effect when <b>-p</b> is set.
+ used to call PCRE. None of the other options has any effect when <b>-p</b> is
+ set.
  </P>
  <P>
  <b>-t</b>
  Run each compile, study, and match many times with a timer, and output
- resulting time per compile or match (in milliseconds). Do not set <b>-t</b> with
+ resulting time per compile or match (in milliseconds). Do not set <b>-m</b> with
- <b>-m</b>, because you will then get the size output 20000 times and the timing
+ <b>-t</b>, because you will then get the size output a zillion times, and the
- will be distorted.
+ timing will be distorted.
  </P>
  <br><a name="SEC3" href="#TOC1">DESCRIPTION</a><br>
  <P>
-Line 85 
 set starts with a regular expression, an
+Line 104 
 set starts with a regular expression, an
  lines to be matched against the pattern.
  </P>
  <P>
- Each line is matched separately and independently. If you want to do
+ Each data line is matched separately and independently. If you want to do
  multiple-line matches, you have to use the \n escape sequence in a single line
  of input to encode the newline characters. The maximum length of data line is
 ,000 characters.
-Line 93 
 of input to encode the newline character
+Line 112 
 of input to encode the newline character
  <P>
  An empty line signals the end of the data lines, at which point a new regular
  expression is read. The regular expressions are given enclosed in any
- non-alphameric delimiters other than backslash, for example
+ non-alphanumeric delimiters other than backslash, for example
- </P>
- <P>
  <pre>
    /(a|bc)x+yz/
- </PRE>
+ </pre>
- </P>
- <P>
  White space before the initial delimiter is ignored. A regular expression may
  be continued over several input lines, in which case the newline characters are
  included within it. It is possible to include the delimiter within the pattern
  by escaping it, for example
- </P>
- <P>
  <pre>
    /abc\/def/
- </PRE>
+ </pre>
- </P>
- <P>
  If you do so, the escape and the delimiter form part of the pattern, but since
- delimiters are always non-alphameric, this does not affect its interpretation.
+ delimiters are always non-alphanumeric, this does not affect its interpretation.
  If the terminating delimiter is immediately followed by a backslash, for
  example,
- </P>
- <P>
  <pre>
    /abc/\
- </PRE>
+ </pre>
- </P>
- <P>
  then a backslash is added to the end of the pattern. This is done to provide a
  way of testing the error condition that arises if a pattern finishes with a
  backslash, because
- </P>
- <P>
  <pre>
    /abc\/
- </PRE>
+ </pre>
- </P>
- <P>
  is interpreted as the first line of a pattern that starts with "abc/", causing
  pcretest to read the next line as a continuation of the regular expression.
  </P>
  <br><a name="SEC4" href="#TOC1">PATTERN MODIFIERS</a><br>
  <P>
- The pattern may be followed by <b>i</b>, <b>m</b>, <b>s</b>, or <b>x</b> to set the
+ A pattern may be followed by any number of modifiers, which are mostly single
- PCRE_CASELESS, PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options,
+ characters. Following Perl usage, these are referred to below as, for example,
- respectively. For example:
+ "the <b>/i</b> modifier", even though the delimiter of the pattern need not
+ always be a slash, and no slash is used when writing modifiers. Whitespace may
+ appear between the final pattern delimiter and the first modifier, and between
+ the modifiers themselves.
  </P>
  <P>
+ The <b>/i</b>, <b>/m</b>, <b>/s</b>, and <b>/x</b> modifiers set the PCRE_CASELESS,
+ PCRE_MULTILINE, PCRE_DOTALL, or PCRE_EXTENDED options, respectively, when
+ <b>pcre_compile()</b> is called. These four modifier letters have the same
+ effect as they do in Perl. For example:
  <pre>
    /caseless/i
- </PRE>
+ </pre>
- </P>
+ The following table shows additional modifiers for setting PCRE options that do
- <P>
+ not correspond to anything in Perl:
- These modifier letters have the same effect as they do in Perl. There are
+ <pre>
- others which set PCRE options that do not correspond to anything in Perl:
+   <b>/A</b>    PCRE_ANCHORED
- <b>/A</b>, <b>/E</b>, and <b>/X</b> set PCRE_ANCHORED, PCRE_DOLLAR_ENDONLY, and
+   <b>/C</b>    PCRE_AUTO_CALLOUT
- PCRE_EXTRA respectively.
+   <b>/E</b>    PCRE_DOLLAR_ENDONLY
- </P>
+   <b>/f</b>    PCRE_FIRSTLINE
- <P>
+   <b>/N</b>    PCRE_NO_AUTO_CAPTURE
+   <b>/U</b>    PCRE_UNGREEDY
+   <b>/X</b>    PCRE_EXTRA
+ </pre>
  Searching for all possible matches within each subject string can be requested
  by the <b>/g</b> or <b>/G</b> modifier. After finding a match, PCRE is called
  again to search the remainder of the subject string. The difference between
-Line 172 
 match is retried. This imitates the way
+Line 185 
 match is retried. This imitates the way
  <b>/g</b> modifier or the <b>split()</b> function.
  </P>
  <P>
- There are a number of other modifiers for controlling the way <b>pcretest</b>
+ There are yet more modifiers for controlling the way <b>pcretest</b>
  operates.
  </P>
  <P>
-Line 184 
 multiple copies of the same substring.
+Line 197 
 multiple copies of the same substring.
  <P>
  The <b>/L</b> modifier must be followed directly by the name of a locale, for
  example,
- </P>
- <P>
  <pre>
-   /pattern/Lfr
+   /pattern/Lfr_FR
- </PRE>
+ </pre>
- </P>
+ For this reason, it must be the last modifier. The given locale is set,
- <P>
- For this reason, it must be the last modifier letter. The given locale is set,
  <b>pcre_maketables()</b> is called to build a set of character tables for the
  locale, and this is then passed to <b>pcre_compile()</b> when compiling the
  regular expression. Without an <b>/L</b> modifier, NULL is passed as the tables
-Line 199 
 pointer; that is, <b>/L</b> applies only
+Line 208 
 pointer; that is, <b>/L</b> applies only
  </P>
  <P>
  The <b>/I</b> modifier requests that <b>pcretest</b> output information about the
- compiled expression (whether it is anchored, has a fixed first character, and
+ compiled pattern (whether it is anchored, has a fixed first character, and
- so on). It does this by calling <b>pcre_fullinfo()</b> after compiling an
+ so on). It does this by calling <b>pcre_fullinfo()</b> after compiling a
- expression, and outputting the information it gets back. If the pattern is
+ pattern. If the pattern is studied, the results of that are also output.
- studied, the results of that are also output.
  </P>
  <P>
  The <b>/D</b> modifier is a PCRE debugging feature, which also assumes <b>/I</b>.
-Line 211 
 compilation. If the pattern was studied,
+Line 219 
 compilation. If the pattern was studied,
  output.
  </P>
  <P>
+ The <b>/F</b> modifier causes <b>pcretest</b> to flip the byte order of the
+ fields in the compiled pattern that contain 2-byte and 4-byte numbers. This
+ facility is for testing the feature in PCRE that allows it to execute patterns
+ that were compiled on a host with a different endianness. This feature is not
+ available when the POSIX interface to PCRE is being used, that is, when the
+ <b>/P</b> pattern modifier is specified. See also the section about saving and
+ reloading compiled patterns below.
+ </P>
+ <P>
  The <b>/S</b> modifier causes <b>pcre_study()</b> to be called after the
  expression has been compiled, and the results used when the expression is
  matched.
-Line 233 
 provided that it was compiled with this
+Line 250 
 provided that it was compiled with this
  causes any non-printing characters in output strings to be printed using the
  \x{hh...} notation if they are valid UTF-8 sequences.
  </P>
- <br><a name="SEC5" href="#TOC1">CALLOUTS</a><br>
- <P>
- If the pattern contains any callout requests, <b>pcretest</b>'s callout function
- will be called. By default, it displays the callout number, and the start and
- current positions in the text at the callout time. For example, the output
- </P>
- <P>
- <pre>
-   ---&#62;pqrabcdef
-   ^  ^
- </PRE>
- </P>
  <P>
- indicates that callout number 0 occurred for a match attempt starting at the
+ If the <b>/?</b> modifier is used with <b>/8</b>, it causes <b>pcretest</b> to
- fourth character of the subject string, when the pointer was at the seventh
+ call <b>pcre_compile()</b> with the PCRE_NO_UTF8_CHECK option, to suppress the
- character. The callout function returns zero (carry on matching) by default.
+ checking of the string for UTF-8 validity.
  </P>
- <P>
+ <br><a name="SEC5" href="#TOC1">DATA LINES</a><br>
- Inserting callouts may be helpful when using <b>pcretest</b> to check
- complicated regular expressions. For further information about callouts, see
- the
- <a href="pcrecallout.html"><b>pcrecallout</b></a>
- documentation.
- </P>
- <P>
- For testing the PCRE library, additional control of callout behaviour is
- available via escape sequences in the data, as described in the following
- section. In particular, it is possible to pass in a number as callout data (the
- default is zero). If the callout function receives a non-zero number, it
- returns that value instead of zero.
- </P>
- <br><a name="SEC6" href="#TOC1">DATA LINES</a><br>
  <P>
  Before each data line is passed to <b>pcre_exec()</b>, leading and trailing
  whitespace is removed, and it is then scanned for \ escapes. Some of these are
-Line 272 
 pretty esoteric features, intended for c
+Line 263 
 pretty esoteric features, intended for c
  complicated features of PCRE. If you are just testing "ordinary" regular
  expressions, you probably don't need any of these. The following escapes are
  recognized:
- </P>
- <P>
  <pre>
    \a         alarm (= BEL)
    \b         backspace
-Line 285 
 recognized:
+Line 274 
 recognized:
    \v         vertical tab
    \nnn       octal character (up to 3 octal digits)
    \xhh       hexadecimal character (up to 2 hex digits)
-   \x{hh...}  hexadecimal character, any number of digits
+   \x{hh...}  hexadecimal character, any number of digits in UTF-8 mode
-                in UTF-8 mode
    \A         pass the PCRE_ANCHORED option to <b>pcre_exec()</b>
    \B         pass the PCRE_NOTBOL option to <b>pcre_exec()</b>
-   \Cdd       call pcre_copy_substring() for substring dd
+   \Cdd       call pcre_copy_substring() for substring dd after a successful match (number less than 32)
-                after a successful match (any decimal number
+   \Cname     call pcre_copy_named_substring() for substring "name" after a successful match (name termin-
-                less than 32)
-   \Cname     call pcre_copy_named_substring() for substring
-                "name" after a successful match (name termin-
                 ated by next non alphanumeric character)
-   \C+        show the current captured substrings at callout
+   \C+        show the current captured substrings at callout time
-                time
    \C-        do not supply a callout function
-   \C!n       return 1 instead of 0 when callout number n is
+   \C!n       return 1 instead of 0 when callout number n is reached
-                reached
+   \C!n!m     return 1 instead of 0 when callout number n is reached for the nth time
-   \C!n!m     return 1 instead of 0 when callout number n is
+   \C*n       pass the number n (may be negative) as callout data; this is used as the callout return value
-                reached for the nth time
+   \D         use the <b>pcre_dfa_exec()</b> match function
-   \C*n       pass the number n (may be negative) as callout
+   \F         only shortest match for <b>pcre_dfa_exec()</b>
-                data
+   \Gdd       call pcre_get_substring() for substring dd after a successful match (number less than 32)
-   \Gdd       call pcre_get_substring() for substring dd
+   \Gname     call pcre_get_named_substring() for substring "name" after a successful match (name termin-
-                after a successful match (any decimal number
-                less than 32)
-   \Gname     call pcre_get_named_substring() for substring
-                "name" after a successful match (name termin-
                 ated by next non-alphanumeric character)
-   \L         call pcre_get_substringlist() after a
+   \L         call pcre_get_substringlist() after a successful match
-                successful match
    \M         discover the minimum MATCH_LIMIT setting
    \N         pass the PCRE_NOTEMPTY option to <b>pcre_exec()</b>
-   \Odd       set the size of the output vector passed to
+   \Odd       set the size of the output vector passed to <b>pcre_exec()</b> to dd (any number of digits)
-                <b>pcre_exec()</b> to dd (any number of decimal
+   \P         pass the PCRE_PARTIAL option to <b>pcre_exec()</b> or <b>pcre_dfa_exec()</b>
-                digits)
+   \R         pass the PCRE_DFA_RESTART option to <b>pcre_dfa_exec()</b>
+   \S         output details of memory get/free calls during matching
    \Z         pass the PCRE_NOTEOL option to <b>pcre_exec()</b>
- </PRE>
+   \?         pass the PCRE_NO_UTF8_CHECK option to <b>pcre_exec()</b>
+   \&#62;dd       start the match at offset dd (any number of digits);
+                this sets the <i>startoffset</i> argument for <b>pcre_exec()</b>
+ </pre>
+ A backslash followed by anything else just escapes the anything else. If the
+ very last character is a backslash, it is ignored. This gives a way of passing
+ an empty line as data, since a real empty line terminates the data input.
  </P>
  <P>
  If \M is present, <b>pcretest</b> calls <b>pcre_exec()</b> several times, with
-Line 331 
 patterns with very large numbers of matc
+Line 317 
 patterns with very large numbers of matc
  very quickly with increasing length of subject string.
  </P>
  <P>
- When \O is used, it may be higher or lower than the size set by the <b>-O</b>
+ When \O is used, the value specified may be higher or lower than the size set
- option (or defaulted to 45); \O applies only to the call of <b>pcre_exec()</b>
+ by the <b>-O</b> command line option (or defaulted to 45); \O applies only to
- for the line in which it appears.
+ the call of <b>pcre_exec()</b> for the line in which it appears.
- </P>
- <P>
- A backslash followed by anything else just escapes the anything else. If the
- very last character is a backslash, it is ignored. This gives a way of passing
- an empty line as data, since a real empty line terminates the data input.
  </P>
  <P>
- If <b>/P</b> was present on the regex, causing the POSIX wrapper API to be used,
+ If the <b>/P</b> modifier was present on the pattern, causing the POSIX wrapper
- only <b>\B</b>, and <b>\Z</b> have any effect, causing REG_NOTBOL and REG_NOTEOL
+ API to be used, only \B and \Z have any effect, causing REG_NOTBOL and
- to be passed to <b>regexec()</b> respectively.
+ REG_NOTEOL to be passed to <b>regexec()</b> respectively.
  </P>
  <P>
  The use of \x{hh...} to represent UTF-8 characters is not dependent on the use
-Line 351 
 of the <b>/8</b> modifier on the pattern
+Line 332 
 of the <b>/8</b> modifier on the pattern
  any number of hexadecimal digits inside the braces. The result is from one to
  six bytes, encoded according to the UTF-8 rules.
  </P>
- <br><a name="SEC7" href="#TOC1">OUTPUT FROM PCRETEST</a><br>
+ <br><a name="SEC6" href="#TOC1">THE ALTERNATIVE MATCHING FUNCTION</a><br>
  <P>
- When a match succeeds, pcretest outputs the list of captured substrings that
+ By default, <b>pcretest</b> uses the standard PCRE matching function,
- <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
+ <b>pcre_exec()</b> to match each data line. From release 6.0, PCRE supports an
- the whole pattern. Here is an example of an interactive pcretest run.
+ alternative matching function, <b>pcre_dfa_test()</b>, which operates in a
+ different way, and has some restrictions. The differences between the two
+ functions are described in the
+ <a href="pcrematching.html"><b>pcrematching</b></a>
+ documentation.
  </P>
  <P>
- <pre>
+ If a data line contains the \D escape sequence, or if the command line
-   $ pcretest
+ contains the <b>-dfa</b> option, the alternative matching function is called.
-   PCRE version 4.00 08-Jan-2003
+ This function finds all possible matches at a given point. If, however, the \F
- </PRE>
+ escape sequence is present in the data line, it stops after the first match is
+ found. This is always the shortest possible match.
+ </P>
+ <br><a name="SEC7" href="#TOC1">DEFAULT OUTPUT FROM PCRETEST</a><br>
+ <P>
+ This section describes the output when the normal matching function,
+ <b>pcre_exec()</b>, is being used.
  </P>
  <P>
+ When a match succeeds, pcretest outputs the list of captured substrings that
+ <b>pcre_exec()</b> returns, starting with number 0 for the string that matched
+ the whole pattern. Otherwise, it outputs "No match" or "Partial match"
+ when <b>pcre_exec()</b> returns PCRE_ERROR_NOMATCH or PCRE_ERROR_PARTIAL,
+ respectively, and otherwise the PCRE negative error number. Here is an example
+ of an interactive <b>pcretest</b> run.
  <pre>
+   $ pcretest
+   PCRE version 5.00 07-Sep-2004
      re&#62; /^abc(\d+)/
    data&#62; abc123
 : abc123
 : 123
    data&#62; xyz
    No match
- </PRE>
+ </pre>
- </P>
- <P>
  If the strings contain any non-printing characters, they are output as \0x
  escapes, or as \x{...} escapes if the <b>/8</b> modifier was present on the
- pattern. If the pattern has the <b>/+</b> modifier, then the output for
+ pattern. If the pattern has the <b>/+</b> modifier, the output for substring 0
- substring 0 is followed by the the rest of the subject string, identified by
+ is followed by the the rest of the subject string, identified by "0+" like
- "0+" like this:
+ this:
- </P>
- <P>
  <pre>
      re&#62; /cat/+
    data&#62; cataract
 : cat
 + aract
- </PRE>
+ </pre>
- </P>
- <P>
  If the pattern has the <b>/g</b> or <b>/G</b> modifier, the results of successive
  matching attempts are output in sequence, like this:
- </P>
- <P>
  <pre>
      re&#62; /\Bi(\w\w)/g
    data&#62; Mississippi
-Line 402 
 matching attempts are output in sequence
+Line 394 
 matching attempts are output in sequence
 : ss
 : ipp
 : pp
- </PRE>
+ </pre>
- </P>
- <P>
  "No match" is output only if the first match attempt fails.
  </P>
  <P>
-Line 420 
 Note that while patterns can be continue
+Line 410 
 Note that while patterns can be continue
  prompt is used for continuations), data lines may not. However newlines can be
  included in data by means of the \n escape.
  </P>
- <br><a name="SEC8" href="#TOC1">AUTHOR</a><br>
+ <br><a name="SEC8" href="#TOC1">OUTPUT FROM THE ALTERNATIVE MATCHING FUNCTION</a><br>
+ <P>
+ When the alternative matching function, <b>pcre_dfa_exec()</b>, is used (by
+ means of the \D escape sequence or the <b>-dfa</b> command line option), the
+ output consists of a list of all the matches that start at the first point in
+ the subject where there is at least one match. For example:
+ <pre>
+     re&#62; /(tang|tangerine|tan)/
+   data&#62; yellow tangerine\D
+: tangerine
+: tang
+: tan
+ </pre>
+ (Using the normal matching function on this data finds only "tang".) The
+ longest matching string is always given first (and numbered zero).
+ </P>
+ <P>
+ If \fB/g\P is present on the pattern, the search for further matches resumes
+ at the end of the longest match. For example:
+ <pre>
+     re&#62; /(tang|tangerine|tan)/g
+   data&#62; yellow tangerine and tangy sultana\D
+: tangerine
+: tang
+: tan
+: tang
+: tan
+: tan
+ </pre>
+ Since the matching function does not support substring capture, the escape
+ sequences that are concerned with captured substrings are not relevant.
+ </P>
+ <br><a name="SEC9" href="#TOC1">RESTARTING AFTER A PARTIAL MATCH</a><br>
+ <P>
+ When the alternative matching function has given the PCRE_ERROR_PARTIAL return,
+ indicating that the subject partially matched the pattern, you can restart the
+ match with additional subject data by means of the \R escape sequence. For
+ example:
+ <pre>
+     re&#62; /^\d?\d(jan|feb|mar|apr|may|jun|jul|aug|sep|oct|nov|dec)\d\d$/
+   data&#62; 23ja\P\D
+   Partial match: 23ja
+   data&#62; n05\R\D
+: n05
+ </pre>
+ For further information about partial matching, see the
+ <a href="pcrepartial.html"><b>pcrepartial</b></a>
+ documentation.
+ </P>
+ <br><a name="SEC10" href="#TOC1">CALLOUTS</a><br>
+ <P>
+ If the pattern contains any callout requests, <b>pcretest</b>'s callout function
+ is called during matching. This works with both matching functions. By default,
+ the called function displays the callout number, the start and current
+ positions in the text at the callout time, and the next pattern item to be
+ tested. For example, the output
+ <pre>
+   ---&#62;pqrabcdef
+   ^  ^     \d
+ </pre>
+ indicates that callout number 0 occurred for a match attempt starting at the
+ fourth character of the subject string, when the pointer was at the seventh
+ character of the data, and when the next pattern item was \d. Just one
+ circumflex is output if the start and current positions are the same.
+ </P>
+ <P>
+ Callouts numbered 255 are assumed to be automatic callouts, inserted as a
+ result of the <b>/C</b> pattern modifier. In this case, instead of showing the
+ callout number, the offset in the pattern, preceded by a plus, is output. For
+ example:
+ <pre>
+     re&#62; /\d?[A-E]\*/C
+   data&#62; E*
+   ---&#62;E*
+    +0 ^      \d?
+    +3 ^      [A-E]
+    +8 ^^     \*
+   +10 ^ ^
+: E*
+ </pre>
+ The callout function in <b>pcretest</b> returns zero (carry on matching) by
+ default, but you can use a \C item in a data line (as described above) to
+ change this.
+ </P>
+ <P>
+ Inserting callouts can be helpful when using <b>pcretest</b> to check
+ complicated regular expressions. For further information about callouts, see
+ the
+ <a href="pcrecallout.html"><b>pcrecallout</b></a>
+ documentation.
+ </P>
+ <br><a name="SEC11" href="#TOC1">SAVING AND RELOADING COMPILED PATTERNS</a><br>
+ <P>
+ The facilities described in this section are not available when the POSIX
+ inteface to PCRE is being used, that is, when the <b>/P</b> pattern modifier is
+ specified.
+ </P>
+ <P>
+ When the POSIX interface is not in use, you can cause <b>pcretest</b> to write a
+ compiled pattern to a file, by following the modifiers with &#62; and a file name.
+ For example:
+ <pre>
+   /pattern/im &#62;/some/file
+ </pre>
+ See the
+ <a href="pcreprecompile.html"><b>pcreprecompile</b></a>
+ documentation for a discussion about saving and re-using compiled patterns.
+ </P>
+ <P>
+ The data that is written is binary. The first eight bytes are the length of the
+ compiled pattern data followed by the length of the optional study data, each
+ written as four bytes in big-endian order (most significant byte first). If
+ there is no study data (either the pattern was not studied, or studying did not
+ return any data), the second length is zero. The lengths are followed by an
+ exact copy of the compiled pattern. If there is additional study data, this
+ follows immediately after the compiled pattern. After writing the file,
+ <b>pcretest</b> expects to read a new pattern.
+ </P>
+ <P>
+ A saved pattern can be reloaded into <b>pcretest</b> by specifing &#60; and a file
+ name instead of a pattern. The name of the file must not contain a &#60; character,
+ as otherwise <b>pcretest</b> will interpret the line as a pattern delimited by &#60;
+ characters.
+ For example:
+ <pre>
+    re&#62; &#60;/some/file
+   Compiled regex loaded from /some/file
+   No study data
+ </pre>
+ When the pattern has been loaded, <b>pcretest</b> proceeds to read data lines in
+ the usual way.
+ </P>
+ <P>
+ You can copy a file written by <b>pcretest</b> to a different host and reload it
+ there, even if the new host has opposite endianness to the one on which the
+ pattern was compiled. For example, you can compile on an i86 machine and run on
+ a SPARC machine.
+ </P>
+ <P>
+ File names for saving and reloading can be absolute or relative, but note that
+ the shell facility of expanding a file name that starts with a tilde (~) is not
+ available.
+ </P>
+ <P>
+ The ability to save and reload files in <b>pcretest</b> is intended for testing
+ and experimentation. It is not intended for production use because only a
+ single pattern can be written to a file. Furthermore, there is no facility for
+ supplying custom character tables for use with a reloaded pattern. If the
+ original pattern was compiled with custom tables, an attempt to match a subject
+ string using a reloaded pattern is likely to cause <b>pcretest</b> to crash.
+ Finally, if you attempt to load a file that is not in the correct format, the
+ result is undefined.
+ </P>
+ <br><a name="SEC12" href="#TOC1">AUTHOR</a><br>
  <P>
- Philip Hazel &#60;ph10@cam.ac.uk&#62;
+ Philip Hazel
  <br>
  University Computing Service,
  <br>
  Cambridge CB2 3QG, England.
  </P>
  <P>
- Last updated: 03 February 2003
+ Last updated: 28 February 2005
  <br>
- Copyright &copy; 1997-2003 University of Cambridge.
+ Copyright &copy; 1997-2005 University of Cambridge.
+ <p>
+ Return to the <a href="index.html">PCRE index page</a>.
+ </p>

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